Answer:
x + f(x) + g(x)
Explanation:
(f+g) = f(x) + g(x)
Therefore, x + (f+g) = x + f(x) + g(x)
If you are given equations to go with f(x) and g(x), you would plug in those equations to the above expression then combine like terms to find the fully simplified expression equal to x + (f+g).